NORTH Korea has reportedly been seen moving a mid-range missile in to position for launch.

South Korean Yonhap news agency reports that North Korea's new KN08 Musudan missile has been spotted in the process of being transported towards the Sea of Japan.

The KN08 Musudan is still under-development and it is unclear if it has the range to reach the United States mainland. Previous assessments have given it a range of 4000km - potentially enough to reach the United States controlled island of Guam.

Any sign of missile movements and preparations is likely to dramatically escalate tensions.